The object of this study is to assess the familial aggregation of outcomes measuring periodontal disease in a population-based family study in the Piedmont area of North Carolina. The study sample includes members of nuclear families ascertained through individuals studied as part of a population-based epidemiologic study of elder North Carolinians,regardless of periodontal status. Clinical, behavioral, and immunological measures were obtained for study. In a subset of these persons, who were found to have severe periodontal disease, extended family structures were sampled. Segregation analyses are planned for this subset of the data.